Implement Mail service.

service/mail/context.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-package user
+package mail
 
 import (
         "golang.org/x/net/context"
 )
 
 type key int
 
 var (
         serviceKey       key
         serviceFilterKey key = 1
 )
 
 // Factory is the function signature for factory methods compatible with
 // SetFactory.
 type Factory func(context.Context) Interface
 
-// Filter is the function signature for a filter user implementation. It
-// gets the current user implementation, and returns a new user implementation
+// Filter is the function signature for a filter mail implementation. It
+// gets the current mail implementation, and returns a new mail implementation
 // backed by the one passed in.
 type Filter func(context.Context, Interface) Interface
 
 // getUnfiltered gets gets the Interface implementation from context without
 // any of the filters applied.
 func getUnfiltered(c context.Context) Interface {
         if f, ok := c.Value(serviceKey).(Factory); ok && f != nil {
                 return f(c)
         }
         return nil
 }
 
 func getCurFilters(c context.Context) []Filter {
         curFiltsI := c.Value(serviceFilterKey)
         if curFiltsI != nil {
                 return curFiltsI.([]Filter)
         }
         return nil
 }
 
-// Get pulls the user service implementation from context or nil if it
+// Get pulls the mail service implementation from context or nil if it
 // wasn't set.
 func Get(c context.Context) Interface {
         ret := getUnfiltered(c)
         if ret == nil {
                 return nil
         }
         for _, f := range getCurFilters(c) {
                 ret = f(c, ret)
         }
         return ret
 }
 
-// SetFactory sets the function to produce user.Interface instances,
+// SetFactory sets the function to produce mail.Interface instances,
 // as returned by the Get method.
 func SetFactory(c context.Context, f Factory) context.Context {
         return context.WithValue(c, serviceKey, f)
 }
 
-// Set sets the user service in this context. Useful for testing with a quick
+// Set sets the mail service in this context. Useful for testing with a quick
 // mock. This is just a shorthand SetFactory invocation to set a factory which
 // always returns the same object.
 func Set(c context.Context, u Interface) context.Context {
         return SetFactory(c, func(context.Context) Interface { return u })
 }
 
 // AddFilters adds Interface filters to the context.
 func AddFilters(c context.Context, filts ...Filter) context.Context {
         if len(filts) == 0 {
                 return c
         }
         cur := getCurFilters(c)
         newFilts := make([]Filter, 0, len(cur)+len(filts))
         newFilts = append(newFilts, getCurFilters(c)...)
         newFilts = append(newFilts, filts...)
         return context.WithValue(c, serviceFilterKey, newFilts)
 }